Prior art fabrics exhibiting desirable drape and conformability characteristics are most typically produced by weaving or knitting processes. However, the labor of weaving or knitting such prior art fabrics is immense. According to Man-Made Fibers by R. W. Moncrieff, John Wiley & Sons, New York, 1975, there will be about six or seven million yarn intersections in a square yard of an ordinary woven jappe. While the loom makes these fairly efficiently, their number sets a limit to the speed with which fabric can be produced. Somewhat similar considerations apply to knitting. There has, therefore, been a considerable incentive to make fabric by methods which avoided the onerous processes of weaving and knitting fabrics either: (a) from film; (b) from felts; (c) from fibers which are bonded or stuck together with some drysetting adhesive to form a felt-like sheet; or by (d) the preparation of similar felt-like sheets on a rubber or plastic backing, usually for carpets; (e) welding of fibers which soften when heated so that one fiber welds to another; (f) bonding with a latent solvent for the fibers; etc.
While prior art nonwoven fabrics are cheaper and less time consuming to produce than the aforementioned knitted and woven fabrics, they generally do not possess the qualities of a woven fabric. Such qualities as drape, hand, and sometimes strength are lacking, since bonding between fibers restricts freedom of motion.
Accordingly, it is an object of the present invention to produce a nonwoven fabric from synthetic monofilament fibers in the form of a regulated chain-mail type structure.
It is a further object of the present invention to prepare a synthetic monofilament fiber that will pass irreversibly from the configuration of a straight rod to that of a substantially closed ring, upon appropriate stimulation, e.g., a change in the surrounding temperature.
It is a further object of the present invention to provide method and apparatus for continuously juxtaposing said treated fiber segments prior to curling so that they will intertwine appropriately to form the aforesaid chain-mail type of structure upon external stimulation.
It is yet another object of the present invention to provide method and apparatus for completing the closure of the ringed, intertwined synthetic fiber segments, e.g., as by a chemical treatment localized at the cut ends of the fiber.